1. Field of the Invention
The present invention relates to a lead wire sealing device, a motor including an electric motor, and a method for sealing a housing through hole formed on a housing member of the motor. Preferably, the motor is utilized by a recording disk drive for driving a recording disk.
2. Description of the Related Art
Conventionally, in a recording disk drive such as a hard disk drive or the like, a through hole is formed on a bracket of a spindle motor and/or a housing of the recording disk drive to connect a lead wire as a part of windings of the spindle motor or the like to a printed circuit board provided in the outside of the housing or the like.
For example, forming a bracket through hole having a lead wire of the windings inserted therein on the bracket of a spindle motor, a through hole is formed on a flexible printed circuit board (hereinafter, referred to as an FPC) and this FPC through hole is located just under this bracket through hole. Further, the size of this FPC through hole is made smaller than that of the bracket through hole and whereby the FPC through hole is fit inside of the bracket through hole and when the lead wire of the windings is pulled out via the bracket through hole and the FPC through hole, the lead wire has little risk to contact directly the inner edge of the bracket through hole. The technology that the lead wire is prevented from contacting the bracket in this way omits a contact protection component such as a rubber tube or the like.
In the meantime, in the hard disk drive, by sealing the closed space of the housing having a recording disk housed therein as separated from the outside, an air around the recording disk is kept clean. Then, in order to prevent air leak to the closed space and maintain a sealed condition, the bracket through hole for pulling out the lead wire formed on the housing is sealed by a sealing material.
On the other hand, in late years, the hard disk drive is also utilized in a car navigation system and high decay durability is required from a car-mounted hard disk drive. For example, in a heating and humidification test, an endurance test of 1,500 hours under temperature 90° C. and humidity 95% is done. In addition, in a heat shock test, an endurance test to repeat cooling and heating for each fifteen minutes under temperatures (−40)° C. and 85° C. alternately 1,500 times is done.
Under such a severe test condition, a sealing material to seal the through hole and an adhesive layer to adhere a circuit board on the housing may be deteriorated. If the adhesive layer is deteriorated, the adhesive layer to adhere the circuit board on the housing is separated from the housing, and a gap is formed between the housing and the circuit board. As a result, a gas may enter the closed space of the housing and the inner air of the housing cannot be kept clean from outside.